Definition: A device that uses a movable mirror to reflect sunlight in a specific direction, often used for measuring solar radiation or in solar energy applications.

Example: The heliostat adjusted its mirror to keep the sunlight focused on the solar panel throughout the day.

Definition: A light, colorless gas that is used in balloons and for cooling. It is the second element on the periodic table and is found in natural gas and some radioactive materials.

Example: The party was fun, especially with the helium balloons floating around.

Definition: A shape or structure that spirals around a central axis, often resembling a coil or spiral staircase.

Example: The DNA molecule has a double helix structure that is essential for its function.

Definition: A device used to count the number of blood cells in a specific volume of blood.

Example: The researcher used a hemacytometer to determine the concentration of red blood cells in the sample.

Definition: A substance that causes red blood cells to clump together, often found in antibodies or certain viruses.

Example: The hemagglutinin in the virus helps it to attach to and infect host cells.

Definition: A reddish-brown crystalline substance used in laboratories as a stain for biological samples and as an indicator in chemical reactions.

Example: The scientist used hematein to stain the tissue samples for better visibility under the microscope.

Definition: A type of mineral that is usually black or reddish-brown and is an important source of iron.

Example: Hematite is often used in jewelry and as a pigment in paints.

Definition: Relating to or resembling a type of iron oxide mineral known as hematite, which is often reddish in color.

Example: The artist used hematitic pigments to create a rich, earthy tone in the painting.

Definition: A chemical compound derived from logwood, used primarily as a dye or stain in biological and histological applications.

Example: The laboratory technician used hematoxylin to stain the tissue samples for examination under the microscope.

Definition: A type of chemical compound that has a specific structure with a hydroxyl group and an alkyl group, often formed during the process of making acetals from aldehydes or ketones.

Example: In organic chemistry, a hemiacetal can be formed when an aldehyde reacts with an alcohol.