Busy. Please wait.

show password
Forgot Password?

Don't have an account?  Sign up 

Username is available taken
show password


Make sure to remember your password. If you forget it there is no way for StudyStack to send you a reset link. You would need to create a new account.
We do not share your email address with others. It is only used to allow you to reset your password. For details read our Privacy Policy and Terms of Service.

Already a StudyStack user? Log In

Reset Password
Enter the associated with your account, and we'll email you a link to reset your password.
Don't know
remaining cards
To flip the current card, click it or press the Spacebar key.  To move the current card to one of the three colored boxes, click on the box.  You may also press the UP ARROW key to move the card to the "Know" box, the DOWN ARROW key to move the card to the "Don't know" box, or the RIGHT ARROW key to move the card to the Remaining box.  You may also click on the card displayed in any of the three boxes to bring that card back to the center.

Pass complete!

"Know" box contains:
Time elapsed:
restart all cards
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.

  Normal Size     Small Size show me how


Year 9 Science Physics Topic 4 Waves and the Earth

Frequency The number of waves passing a point each second.
Hertz (Hz) The unit for frequency 1 hertz is 1 wave per second.
Longitudinal E.g. sound waves where the direction of energy transfer is parallel with the direction of movement of the energy.
Medium Something through which waves travel.
Pitch Whether a sound is low or high.
Infrasound Sound waves with a frequency below 20Hz which is too low for the human ear to detect.
Ultrasound Sound waves with a frequency above 20000Hz which is too high for the human ear to detect.
Reflect When a wave bounces off a boundary between two materials.
Sonar A way of finding the distance to an underwater object (such as the sea floor) by timing how long it takes for a pulse of ultrasound to be reflected.
Ultrasounds scan A way of making an image of part of the body (usually a foetus) using ultrasound waves reflected from parts of the inside of the body.
Earthquake A sudden movement within the Earth releasing a large amount of stored energy.
Seismic waves Waves produced by an explosion or earthquake and which travels through the Earth. They include P-waves and S-waves.
Seismometer An instrument that detects seismic waves.
Focus The place where an earthquake begins usually under the surface.
Epicenter The point on the surface of the Earth directly above the focus of an earthquake.
P waves Longitudinal seismic waves that travel through the Earth.
S waves Transverse seismic waves that travel through the Earth.
Crust The outer surface of the Earth.
Mantle The part of the Earth between the crust and the core.
Core The middle of the Earth.
Refraction The chang of speed and direction of a wave when it enters a new material.
Plates Sections of the outermost layer of the Earth that can move relative to each other.
Tectonic plates Pieces of the surface of the Earth which can move around very slowly.
Convection currents A current caused by parts of a fluid being at a different temperature and so a different density to the rest of the fluid.
Tsunami A huge wave caused by an earthquake or landslide on the sea bed.
Created by: bookcase