HMH Science Dimensions: Grade 8

Energy Conversions

Where does energy come from? How does energy get from one place to another? Find out how electrical current is generated and how living things get energy to move and grow. Trace the path of energy and see how energy is converted from one form to another.5 Minute Preview

能源的摆

Perform experiments with a pendulum to gain an understanding of energy conservation in simple harmonic motion. The mass, length, and gravitational acceleration of the pendulum can be adjusted, as well as the initial angle. The potential energy, kinetic energy, and total energy of the oscillating pendulum can be displayed on a table, bar chart or graph.5 Minute Preview

Inclined Plane - Sliding Objects

Investigate the energy and motion of a block sliding down an inclined plane, with or without friction. The ramp angle can be varied and a variety of materials for the block and ramp can be used. Potential and kinetic energy are reported as the block slides down the ramp. Two experiments can be run simultaneously to compare results as factors are varied.5 Minute Preview

Potential Energy on Shelves

Compare the potential energy of several objects when you place them on shelves of different heights. Learn that two objects at different heights can have the same potential energy, while two objects at the same height can have different potential energies.5 Minute Preview

Roller Coaster Physics

Adjust the hills on a toy-car roller coaster and watch what happens as the car careens toward an egg (that can be broken) at the end of the track. The heights of three hills can be manipulated, along with the mass of the car and the friction of the track. A graph of various variables of motion can be viewed as the car travels, including position, speed, acceleration, potential energy, kinetic energy, and total energy.5 Minute Preview

Sled Wars

Explore acceleration, speed, momentum, and energy by sending a sled down a hill into a group of snowmen. The starting height and mass of the sled can be changed, as well as the number of snowmen. In the Two sleds scenario, observe collisions between sleds of different masses and starting heights.5 Minute Preview

Trebuchet

Design your own trebuchet to fling a projectile at a castle wall. All of the dimensions of the trebuchet can be adjusted, as well as the masses of the counterweight and payload. Select a target on the Launch tab, or just see how far your projectile will go.5 Minute Preview

Fan Cart Physics

Gain an understanding of Newton's Laws by experimenting with a cart (on which up to three fans are placed) on a linear track. The cart has a mass, as does each fan. The fans exert a constant force when switched on, and the direction of the fans can be altered as the position, velocity, and acceleration of the cart are measured.5 Minute Preview

Force and Fan Carts

Explore the laws of motion using a simple fan cart. Use the buttons to select the speed of the fan and the surface, and press Play to begin. You can drag up to three objects onto the fan cart. The speed of the cart is displayed with a speedometer and recorded in a table and a graph.5 Minute Preview

Free-Fall Laboratory

Investigate the motion of an object as it falls to the ground. A variety of objects can be compared, and their motion can be observed in a vacuum, in normal air, and in denser air. The position, velocity, and acceleration are measured over time, and the forces on the object can be displayed. Using the manual settings, the mass, radius, height, and initial velocity of the object can be adjusted, as can the air density and wind.5 Minute Preview

Crumple Zones

Design a car to protect a test dummy in a collision. Adjust the length and stiffness of the crumple zone and the rigidity of the safety cell to determine how the car will deform during the crash. Add seat belts and/or airbags to prevent the dummy from hitting the steering wheel. Three different body types (sedan, SUV, and subcompact) are available and a wide range of crash speeds can be used.5 Minute Preview

Distance-Time Graphs

Create a graph of a runner's position versus time and watch the runner complete a 40-yard dash based on the graph you made. Notice the connection between the slope of the line and the speed of the runner. What will the runner do if the slope of the line is zero? What if the slope is negative? Add a second runner (a second graph) and connect real-world meaning to the intersection of two graphs.5 Minute Preview

Fan Cart Physics

Gain an understanding of Newton's Laws by experimenting with a cart (on which up to three fans are placed) on a linear track. The cart has a mass, as does each fan. The fans exert a constant force when switched on, and the direction of the fans can be altered as the position, velocity, and acceleration of the cart are measured.5 Minute Preview

Force and Fan Carts

Explore the laws of motion using a simple fan cart. Use the buttons to select the speed of the fan and the surface, and press Play to begin. You can drag up to three objects onto the fan cart. The speed of the cart is displayed with a speedometer and recorded in a table and a graph.5 Minute Preview

Measuring Motion

Go on an African safari and observe a variety of animals walking and running across the savanna. Videotape the animals, and then play back the videotape to estimate animal speeds. Which animals run fastest?5 Minute Preview

Radiation

Use a powerful flashlight to pop a kernel of popcorn. A lens focuses light on the kernel. The temperature of the filament and the distance between the flashlight and lens can be changed. Several obstacles can be placed between the flashlight and the popcorn.5 Minute Preview

Crumple Zones

Design a car to protect a test dummy in a collision. Adjust the length and stiffness of the crumple zone and the rigidity of the safety cell to determine how the car will deform during the crash. Add seat belts and/or airbags to prevent the dummy from hitting the steering wheel. Three different body types (sedan, SUV, and subcompact) are available and a wide range of crash speeds can be used.5 Minute Preview

Charge Launcher

Launch a charged particle into a chamber. Charged particles can be added into the chamber to influence the path of the moving particle. The launch speed can be changed as well. Try to match a given path by manipulating the fixed particles in the chamber.5 Minute Preview

Electromagnetic Induction

Explore how a changing magnetic field can induce an electric current. A magnet can be moved up or down at a constant velocity below a loop of wire, or the loop of wire may be dragged in any direction or rotated. The magnetic and electric fields can be displayed, as well as the magnetic flux and the current in the wire.5 Minute Preview

Magnetic Induction

Measure the strength and direction of the magnetic field at different locations in a laboratory. Compare the strength of the induced magnetic field to Earth's magnetic field. The direction and magnitude of the inducting current can be adjusted.5 Minute Preview

Magnetism

Drag bar magnets and a variety of other objects onto a piece of paper. Click Play to release the objects to see if they are attracted together, repelled apart, or unaffected. You can also sprinkle iron filings over the magnets and other objects to view the magnetic field lines that are produced.5 Minute Preview

Gravitational Force

Drag two objects around and observe the gravitational force between them as their positions change. The mass of each object can be adjusted, and the gravitational force is displayed both as vectors and numerically.5 Minute Preview

Magnetic Induction

Measure the strength and direction of the magnetic field at different locations in a laboratory. Compare the strength of the induced magnetic field to Earth's magnetic field. The direction and magnitude of the inducting current can be adjusted.5 Minute Preview

Magnetism

Drag bar magnets and a variety of other objects onto a piece of paper. Click Play to release the objects to see if they are attracted together, repelled apart, or unaffected. You can also sprinkle iron filings over the magnets and other objects to view the magnetic field lines that are produced.5 Minute Preview

Gravity Pitch

Imagine a gigantic pitcher standing on Earth, ready to hurl a huge baseball. What will happen as the ball is thrown harder and harder? Find out with the Gravity Pitch Gizmo. Observe the path of the ball when it is thrown at different velocities. Throw the ball on different planets to see how each planet's gravity affects the ball.5 Minute Preview

Magnetic Induction

Measure the strength and direction of the magnetic field at different locations in a laboratory. Compare the strength of the induced magnetic field to Earth's magnetic field. The direction and magnitude of the inducting current can be adjusted.5 Minute Preview

Weight and Mass

Use a balance to measure mass and a spring scale to measure the weight of objects. Compare the masses and weights of objects on Earth, Mars, Jupiter, and the Moon.5 Minute Preview

Seasons Around the World

Use a three dimensional view of the Earth, Moon and Sun to explore seasonal changes at a variety of locations. Strengthen your knowledge of global climate patterns by comparing solar energy input at the Poles to the Equator. Manipulate Earth's axis to increase or diminish seasonal changes.5 Minute Preview

Seasons in 3D

Gain an understanding of the causes of seasons by observing Earth as it orbits the Sun in three dimensions. Observe the path of the Sun across the sky on any date and from any location. Create graphs of solar intensity and day length, and use collected data to describe and explain seasonal changes.5 Minute Preview

Seasons: Earth, Moon, and Sun

Observe the motions of the Earth, Moon and Sun in three dimensions to explain Sunrise and Sunset, and to see how we define a day, a month, and a year. Compare times of Sunrise and Sunset for different dates and locations. Relate shadows to the position of the Sun in the sky, and relate shadows to compass directions.5 Minute Preview

Seasons: Why do we have them?

Learn why the temperature in the summertime is higher than it is in the winter by studying the amount of light striking the Earth. Experiment with a plate detector to measure the amount of light striking the plate as the angle of the plate is adjusted (and then use a group of plates placed at different locations on the Earth) and measure the incoming radiation on each plate.5 Minute Preview

Solar System

Explore our solar system and learn the characteristics of each planet. Compare the sizes of planets and their distances from the Sun. Observe the speeds of planetary orbits and measure how long each planet takes to go around the Sun.5 Minute Preview

Summer and Winter

Observe the tilt of Earth's axis and the angle that sunlight strikes Earth on June 21 and December 21. Compare day lengths, temperatures, and the angle of the Sun's rays for any latitude. The tilt of the Earth's axis can be varied to see how this would affect seasons.5 Minute Preview

2D Eclipse

Manipulate the position of the Moon to model solar and lunar eclipses. View Earth's shadow, the Moon's shadow, or both. Observe the Moon and Sun from Earth during a partial and total eclipse. The sizes of the three bodies and the Earth-Moon distance can be adjusted.5 Minute Preview

3D Eclipse

Observe the motions of the Earth, Moon and Sun in three dimensions to investigate the causes and frequency of eclipses. Observe Earth's shadow crossing the Moon during a lunar eclipse, and the path of the Moon's shadow across Earth's surface during a solar eclipse. The angle of the Moon's orbit can be adjusted, as well as the distance of the Moon from the Earth.5 Minute Preview

Eclipse

Observe solar and lunar eclipses as the Moon orbits Earth. The full and partial shadows of the Moon and Earth can be displayed, and the Moon can also be dragged around Earth. See what the Moon and Sun look like from Earth during partial and total eclipses.5 Minute Preview

Moonrise, Moonset, and Phases

Gain an understanding of moonrise and moonset times by observing the relative positions of Earth and the Moon along with a view of the Moon from Earth. A line shows the horizon for a person standing on Earth so that moonrise and moonset times can be determined.5 Minute Preview

Phases of the Moon

Understand the phases of the Moon by observing the positions of the Moon, Earth and Sun. A view of the Moon from Earth is shown on the right as the Moon orbits Earth. Learn the names of Moon phases and in what order they occur. Click Play to watch the Moon go around, or click Pause and drag the Moon yourself.5 Minute Preview

Gravity Pitch

Imagine a gigantic pitcher standing on Earth, ready to hurl a huge baseball. What will happen as the ball is thrown harder and harder? Find out with the Gravity Pitch Gizmo. Observe the path of the ball when it is thrown at different velocities. Throw the ball on different planets to see how each planet's gravity affects the ball.5 Minute Preview

Solar System

Explore our solar system and learn the characteristics of each planet. Compare the sizes of planets and their distances from the Sun. Observe the speeds of planetary orbits and measure how long each planet takes to go around the Sun.5 Minute Preview

Solar System Explorer

Survey the solar system, observing the length of a year and the orbital path of each object. The positions of the eight official planets are displayed, as well as one dwarf planet, Pluto. Learn about Kepler's Laws and how planets are classified.5 Minute Preview

Embryo Development

Explore how a fertilized cell develops into an embryo, a fetus, and eventually an adult organism. Compare embryo development in different vertebrate species and try to guess which embryo belongs to each species. Use dyes to trace the differentiation of cells during early embryo development, from the zygote to the neurula.5 Minute Preview

Human Evolution - Skull Analysis

比较各种重要的头骨的嗡嗡声an ancestors, or hominids. Use available tools to measure lengths, areas, and angles of important features. Each skull can be viewed from the front, side, or from below. Additional information regarding the age, location, and discoverer of each skull can be displayed.5 Minute Preview

Microevolution

Observe the effect of predators on a population of parrots with three possible genotypes. The initial percentages and fitness levels of each genotype can be set. Determine how initial fitness levels affect genotype and allele frequencies through several generations. Compare scenarios in which a dominant allele is deleterious, a recessive allele is deleterious, and the heterozygous individual is fittest.5 Minute Preview

Evolution: Mutation and Selection

Observe evolution in a fictional population of bugs. Set the background to any color, and see natural selection taking place. Inheritance of color occurs according to Mendel's laws and probability. Mutations occur at random, and probability of capture by predators is determined by the insect's camouflage.5 Minute Preview

Evolution: Natural and Artificial Selection

Observe evolution in a fictional population of bugs. Set the background to any color, and see natural selection taking place. Compare the processes of natural and artificial selection. Manipulate the mutation rate, and determine how mutation rate affects adaptation and evolution.5 Minute Preview

Microevolution

Observe the effect of predators on a population of parrots with three possible genotypes. The initial percentages and fitness levels of each genotype can be set. Determine how initial fitness levels affect genotype and allele frequencies through several generations. Compare scenarios in which a dominant allele is deleterious, a recessive allele is deleterious, and the heterozygous individual is fittest.5 Minute Preview

Natural Selection

You are a bird hunting moths (both dark and light) that live on trees. As you capture the moths most easily visible against the tree surface, the moth populations change, illustrating the effects of natural selection.5 Minute Preview

Rainfall and Bird Beaks

Study the thickness of birds' beaks over a five-year period as you control the yearly rainfall on an isolated island. As the environmental conditions change, the species must adapt (a real-world consequence) to avoid extinction.5 Minute Preview

Rainfall and Bird Beaks - Metric

Study the thickness of birds' beaks over a five year period as you control the yearly rainfall on an isolated island. As the environmental conditions change, the species must adapt (a real-world consequence) to avoid extinction.5 Minute Preview

Evolution: Natural and Artificial Selection

Observe evolution in a fictional population of bugs. Set the background to any color, and see natural selection taking place. Compare the processes of natural and artificial selection. Manipulate the mutation rate, and determine how mutation rate affects adaptation and evolution.5 Minute Preview

GMOs and the Environment

In this follow-up to the Genetic Engineering Gizmo, explore how farmers can maximize yield while limiting ecosystem damage using genetically modified corn. Choose the corn type to plant and the amount of herbicide and insecticide to use, then measure corn yields and monitor wildlife populations and diversity. Observe the long-term effects of pollutants on a nearby stream ecosystem.5 Minute Preview

Genetic Engineering

Use genetic engineering techniques to create corn plants resistant to insect pests or tolerant of herbicides. Identify useful genes from bacteria, insert the desired gene into a corn plant, and then compare the modified plant to a control plant in a lab setting.5 Minute Preview

Longitudinal Waves

Observe the propagation of longitudinal (compression) waves in a closed or open tube with evenly-spaced dividers. The strength and frequency of the waves can be manipulated, or waves can be observed as individual pulses. Compare the movement of dividers to graphs of displacement, velocity, acceleration and pressure.5 Minute Preview

Waves

Observe and measure transverse, longitudinal, and combined waves on a model of a spring moved by a hand. Adjust the amplitude and frequency of the hand, and the tension and density of the spring. The speed and power of the waves is reported, and the wavelength and amplitude can be measured.5 Minute Preview

Earthquakes 1 - Recording Station

Using an earthquake recording station, learn how to determine the distance between the station and an earthquake based on the time difference between the arrival of the primary and secondary seismic waves. Use this data to find the epicenter in the Earthquakes 2 - Location of Epicenter Gizmo.5 Minute Preview

Longitudinal Waves

Observe the propagation of longitudinal (compression) waves in a closed or open tube with evenly-spaced dividers. The strength and frequency of the waves can be manipulated, or waves can be observed as individual pulses. Compare the movement of dividers to graphs of displacement, velocity, acceleration and pressure.5 Minute Preview

Ripple Tank

Study wave motion, diffraction, interference, and refraction in a simulated ripple tank. A wide variety of scenarios can be chosen, including barriers with one or two gaps, multiple wave sources, reflecting barriers, or submerged rocks. The wavelength and strength of waves can be adjusted, as well as the amount of damping in the tank.5 Minute Preview

Sound Beats and Sine Waves

Listen to and see interference patterns produced by sound waves with similar frequencies. Test your ability to distinguish and match sounds as musicians do when they tune their instruments. Calculate the number of "sound beats" you will hear based on the frequency of each sound. [Note: Headphones are recommended for this Gizmo.]5 Minute Preview

Waves

Observe and measure transverse, longitudinal, and combined waves on a model of a spring moved by a hand. Adjust the amplitude and frequency of the hand, and the tension and density of the spring. The speed and power of the waves is reported, and the wavelength and amplitude can be measured.5 Minute Preview

Basic Prism

Shine white light or a single-color beam through a prism. Explore how a prism refracts light and investigate the factors that affect the amount of refraction. The index of refraction of the prism, width of the prism, prism angle, light angle, and light wavelength can be adjusted.5 Minute Preview

Color Absorption

Mix the primary colors of light by using red, green, and blue lights. Use pieces of colored glass to filter the light and create a wide variety of colors. Determine how light is absorbed and transmitted by each color of glass.5 Minute Preview

Eyes and Vision 1 - Seeing Color

Observe how different colors of light are reflected or absorbed by colored objects. Determine that white light is a combination of different colors of light, and that one or more component colors may be reflected when white light is shone on an object. Understand that we see an object when light reflected from the object enters our eye.5 Minute Preview

Laser Reflection

Point a laser at a mirror and compare the angle of the incoming beam to the angle of reflection. A protractor can be used to measure the angles of incidence and reflection, and the angle of the mirror can be adjusted. A beam splitter can be used to split the beam. Both plane and irregular mirrors can be used.5 Minute Preview

Refraction

确定光束的折射角moving from one medium to another. The angle of incidence and each index of refraction can be varied. Using the tools provided, the angle of refraction can be measured, and the wavelength and frequency of the waves in each substance can be compared as well.5 Minute Preview

Seasons Around the World

Use a three dimensional view of the Earth, Moon and Sun to explore seasonal changes at a variety of locations. Strengthen your knowledge of global climate patterns by comparing solar energy input at the Poles to the Equator. Manipulate Earth's axis to increase or diminish seasonal changes.5 Minute Preview

Seasons in 3D

Gain an understanding of the causes of seasons by observing Earth as it orbits the Sun in three dimensions. Observe the path of the Sun across the sky on any date and from any location. Create graphs of solar intensity and day length, and use collected data to describe and explain seasonal changes.5 Minute Preview

Seasons: Earth, Moon, and Sun

Observe the motions of the Earth, Moon and Sun in three dimensions to explain Sunrise and Sunset, and to see how we define a day, a month, and a year. Compare times of Sunrise and Sunset for different dates and locations. Relate shadows to the position of the Sun in the sky, and relate shadows to compass directions.5 Minute Preview

Seasons: Why do we have them?

Learn why the temperature in the summertime is higher than it is in the winter by studying the amount of light striking the Earth. Experiment with a plate detector to measure the amount of light striking the plate as the angle of the plate is adjusted (and then use a group of plates placed at different locations on the Earth) and measure the incoming radiation on each plate.5 Minute Preview

Summer and Winter

Observe the tilt of Earth's axis and the angle that sunlight strikes Earth on June 21 and December 21. Compare day lengths, temperatures, and the angle of the Sun's rays for any latitude. The tilt of the Earth's axis can be varied to see how this would affect seasons.5 Minute Preview

Carbon Cycle

Follow the path of a carbon atom through the atmosphere, biosphere, hydrosphere, and geosphere. Manipulate a simplified model to see how human activities and other factors affect the amount of atmospheric carbon today and in the future.5 Minute Preview

Coral Reefs 2 - Biotic Factors

In this followup to the Coral Reefs 1 - Abiotic Factors activity, investigate the impacts of fishing, disease, and invasive species on a model Caribbean coral reef. Many variables can be manipulated, included intensity of fishing, presence of black band and white band disease, and the presence of actual and potential invasive species. Click "Advance year" to see the impacts of these biotic changes.5 Minute Preview